Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well past the annotations (readOnly/idempotent/closed-world) to disclose that late arrivals and source revisions mutate the report, that ordering is attention-based rather than risk-probability, that counts are collected evidence and absence is not proof of safety, and that source text is untrusted data. It also specifies operational behavior: sequential calls on the public endpoint and that HTTP 429 with Retry-After means admission denial, not an empty result.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The window definition and mutability caveat are front-loaded, which is good, but the description runs to roughly ten sentences for a zero-required-parameter read tool. Several ideas repeat (counts vs. attacks, absence not proof, caveats/citations), so it is dense rather than lean.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description still signals what comes back (findings, caveats, citations, counts) and covers the clock window, mutability, trust handling, and rate-limit recovery. It stops short of describing the actual response fields or pagination, which is the remaining gap for a tool with no output schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Only one optional parameter (limit) exists and the schema documents it fully at 100% coverage, so the baseline is 3. The description adds nothing about limit — neither its default/ceiling nor how it interacts with the bounded report — so it does not exceed the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Read a bounded daily report of public-source Threat Intel') with an explicit scope: the previous complete UTC day, selected by source-effective publishedAt. It never names a sibling (ti_latest, ti_get, ti_trends) to draw the boundary, so differentiation is inferable but not explicit.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage context is clear — a fixed, non-overridable previous-day window and a note that this is a current view rather than a snapshot. However, there is no explicit 'use this instead of ti_latest when…' routing, so an agent must infer the choice between this and its five siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.